With a conventional vehicle-mounted electronic apparatus, in order to miniaturize and lower the cost of a control unit, a heating block and others are made unnecessary by connecting heat-generating electronic components to a metallic wiring board (see, for example, patent literature 1). Also, with a general vehicle-mounted electronic apparatus, in order to release the heat produced by heat-generating electronic components, a heat-sink plate is insert-molded in the bottom surface of a case, and heat-generating electronic components are placed on this heat-sink plate (see, for example, patent literature 2).